Sweep circuit



May 10, 1955 R. F. CASEY 2,703,240

SWEEP CIRCUIT Filed April 26. 1952' 3 Sheets-Sheet 1 INVENTOR. ROBERT F:CASEY ATTORNEYS May 10, 1955 R. F. CASEY 2,703,240

SWEEP CIRCUIT Filed April 26. 1952 3 Sheets-Sheet 2 INVENTOR.ROBERTECASEY ATTORNEYS R. F. CASEY May 10, 1955 SWEEP CIRCUIT 3Sheets-Sheet 3 Filed April 26, 1952 INVENTOR. ROBERT F. CASEY Md 17 l AT TORNEYS United Stats SWEE? CIRQUIT Robert F. Casey, Pompton Plains, N.3., assignor to Allen B. Du Mont Laboratories, Inc., Clifton, N. 5., acorporan'on G1 Delaware Application April 2b, 1952, Serial No. 284,609

17 Claims. (Cl. 250-27) This invention relates to electrical circuitsand particularly to circuits for producing sawtooth voltage waves. SuchWaves are useful, for example, in causing an electron beam to scan a.phosphor screen in a cathode-ray tube.

An object of the invention is to provide a generator for producing recurent high-speed electrical signals, the rate of recurrence being variableby adjustment of a single time-constant circuit.

Another object of the invention is to provide a circuit for generatingselectively recurrent or non-recurrent linear sawtooth waves havinuniform characteristics and rapid retrace times.

A further object is to provide a circuit for generating push-pull squarewaves.

Another object is to provide a bi-stable square wave generator therepetition rate of which is controlled by a single time-constantcircuit.

Other objects will be apparent.

In the drawings,

Figure 1 is a schematic diagram of a preferred embodiment of theinvention;

Figures 2 and 3 are schematic diagrams of modifications of the circuitof Figure 1, incorporating features which provide increased stability ofoperation;

Figure 4 is a schematic diagram showing a modification of a portion ofthe circuit of Figure 1, which provides a push-pull square wave signal;and

Figure 5 is a schematic diagram of a circuit which may be incorporatedin the circuits of Figures 1, 2 or 3 in order to increase the speed ofoperation.

In Figure 1, a source 11 of negative polarity synchronizing signals isconnected to a second grid 12 of a timing tube 13 which preferably is ofthe type known as a gated-bearn tube, such as the tube type No. 6BN6.

This second grid is sometimes referred to as a quadrature grid. Thesecond grid 12 is returned to ground through a resistance 14, and acathode 16 is grounded. An anode 17 and a collector electrode 18 areconnected, through load resistances 21 and 22, respectively, to a source19 of voltage having positive polarity. The resistance 22 is preferablyadjustable.

A control electrode 26 of a coupling tube 27 is connected to thecollector element 18 through a constantvoltage device 28 shown as havingan anode 31 and a cathode 32. The constant-voltage device 28 may be agas-filled tube, a piece of thyrite, or the like. The control electrodeis also connected through a resistance 33 to a source 34 of voltagehaving negative polarity. An anode 36 is connected to the voltage source19. A cathode 37 is connected through a resistance 38 to the voltagesource 34 and also through a resistance 39 to a first grid 41 in thetiming tube 13, andalso to a control electrode 46 of a discharge tube47, a cathode 48 of which is grounded.

An anode 49 of the discharge tube 47 is connected to the voltage source19 through a variable resistance 51 and a fixed resistance 52. The anode49 is also connected to a condenser 56 and to a control electrode 57 or"an output tube 53 having an anode 61 connected to the source 19 ofvoltage, and a cathode 62 connected through a load resistance 64 to thesource 34 of voltage. The cathode 62 of the output tube 58 is connectedthrough a constant-voltage device 66 to the junction between the fixedresistance 52 and the variable resistance 51, a cathode 67 of the device66 being shown connected to the cathode 62 and an anode 68 being shownconnected to the junction. An output terminal 71 is connected to thecathode 62. A feedback resistance 72 is connected between a tap '73 onthe load resistance 6s and the first grid 41 of the timing tube 13.

In the figures of the drawings, like parts are designated by likereference numerals. Figure 2 includes, in addition to the elements shownin Figure 1, a feedback tube 76 having an anode 77 connected to thevoltage source 19, a cathode 73 connected to the cathode 43 of thedischarge tube 47 and through a resistance 7 to ground, and a controlelectrode 81 connected to a tap 82 on the load resistance 64. Thepurpose of the feedback tube 76 is to increase the operating stability,as will be described hereinafter. In Figure 2, the constant-voltagedevice 28 is shown connected in series with the cathode 37 of thecoupling tube 27, instead of in series with the grid 26 of this tube asis shown in Figure 1. The resistance 33 connected to the grid 26 of thecoupling tube 27 in Figure l, is omitted in Figure 2. The purpose ofthese latter changes is to provide suitable operating potentials for thetube elements.

In Figure 3, the feedback resistance 72 of Figure 1 is replaced by adiode rectifier device 83 having an anode connected to the tap 73 and acathode connected to the first grid ll of the timing tube 13. Aresistance 84 is connected between the cathode 37 of the coupling tube27 and the control electrode 46 of the discharge tube 47, for thepurpose of obtaining proper operating voltages. The constant voltagedevice 28 is connected in the circuit in a manner similar to itsconnection shown in Figure 2.

The part of the circuit comprising the discharge tube 47, the condenser56, the output tube 58, the constantvoltage device 66, and associatedcomponents, is more fully described in copending application Serial No.284,611, by the same inventor and assigned to the same assignee.

In Figure 4, the source 11 of negative-polarity synchronizing signals isconnected to the second grid 12 of the timing tube 13, and also to aninput terminal 91 of a source 92 of variable phase positive polaritytrigger signals having an output terminal 93 which may be connectedthrough a switch 94 to the first grid 41 of the timing tube 13. The loadresistances 21 and 22 are connected beween the voltage source 19 and theanode l7 and collector electrode 18 as has been described in connectionwith Figures l, 2 and 3. The collector electrode 18 is connected througha constant-voltage device 28 to the first grid 41. The cathode 16 isgrounded. A first output terminal 101 is counectel to the anode i7. Asecond output terminal 102 is connected to the collector electrode 18. Aphase delay device M53 is connected between the anode 17 and the switch4 so that it may be selectively connected to the first grid 41.

In the modified circuit of Figure 5, the cathode load resistance 38 ofthe coupling tube 27 shown in Figures 1, 2 and 3 is replaced with anelectronic tube 95, preferably of the pentode type, having an anode 96connected jointly to the resistance 84 and the control electrodes 41 and46 of the tubes 13 and 4-7 respectively. A screen grid 97 is grounded. Acathode 93 is connected through a variable resistance 99 to the negativevoltage source 34. A control electrode 100 is connected through aresistance 104 to the relatively less positive.

trons from the cathode 16 will flow to the anode l7, irreavoaaao voltagesource 34,and through a capacitance 1% to the anode 17 of the timingtubelS. A stray capacitance 11H) occurs in the circuit between groundand the elements of the tubes 13, 47 and 95.

Before describing the operation of the invention, it will be expedientto describe the function and operation of the timing tube 13. Byconnecting proper voltage to this tube, it is possible to cause the tubeto have two stable states of operation. For the first stable state, boththe first grid 41 and the second grid 12 are caused to have voltagepolarities with respect to the cathode 15 such that electrons from thecathode in will flow through both grids to the positive-polarity anode17, and thus a current will flow through the anode load resistance 21.In this first stable state, no appreciable amount of electrons from thecathode 16 flows to the collector electrode 13; hence, there is noappreciable current flowing through the collector load resistanceZZ, andthus the collector electrode assumes approximately the positive-polarityvoltage of the source 19.

In the second stable state of the tube 3.3, the voltage of the firstgrid 41 is changed to be relatively negative in polarity with respect toits voltage for the first stable state. This voltage is usually negativewith respect to the voltage of the cathode l6. Electrons from thecafnode 16 will then flow directly to'the collector electrode 13, andthus appreciable current will flow through the collector load resistance22, and the collector potential will become Under these conditions, noelecspective of whether the second grid 12 is made to have a positive ora negative polarity. Hence, no appreciable current will 'fiow throughthe anode load resistance 21 in the second stable state. The tube 13effectively has two output electrodes; the anode 17 and the collectorelectrode 18.

The invention operates as follows: (refer to Figures 1 and 2). Normallythe timing tube 13 will be in its first stable state, with currentflowing to the anode and only a small amount flowing to the collectorelectrode. When a negative polarity pulse from the source 11 is appliedto the second grid 12 of the timing tube 23, the electron current in thetube that was flowing to the anode, will now fiow to the collectorelectrode 18, through the firstgrid 41. This causes current to flowthrough the collector load resistance 22, thereby causing the collectorelectrode 18 to quickly become relatively negative with respect to itsoriginal potential. The tube now .is in a transition state, withelectrons flowing from the cathode to the collector through the firstgrid.

The negative change in potential of the collector 18 is quicklytransmitted, by alternative means in the two preferred embodiments ofFigures 1 and 2, to the first grid 41 of the gated beam tube. In thecircuit of Figure l, the negative change .in potential of the collectorelectrode 18 is transmitted through the constant-voltage device 2% tothe control electrode 26 of the coupling tube 27. Since the'tube 27 isconnected in a cathode-follower circuit, the voltage on its cathode 37will assume a relatively negative change in polarity, which change isapplied through the resistance 39 to the first grid 41 or" the timingtube 13.

In the circuit of Figure 2, the negative change in potential of thecollector electrode 18 is directly applied to the grid 25 of thecoupling tube 27. This causes the voltage of the cathode 37 to becomerelatively negative, this negative voltage change being transmittedthrough the constant-voltage device 28 and the resistance 39 to thefirst grid 41 of the timing tube 13.

When the first grid 41 or" the timing tube 13 is thus quickly maderelatively negative, current ceases to flow through it to the collector18 and instead flows directly to the collector electrode 3.3. The tube13 has thus quickly changed from its stable state through a transitionstate, and then to its second stable state, and will remain in thissecond stablestate aslong as the first grid polarity of voltage of thesecond grid 12.

fore described, is applied to the control electrode 46 of I thedischarge tube 47, which normally is in a conducting state therebynormally maintaining the condenser 56 in a discharged condition. Thedischarge tube 47 is quickly made substantially non-conductive when itscontrol electrode is rendered negative in voltage polarity, and thecondenser 56 then begins to charge from the voltage source 19 throughthe resistances 51 and 52.. As the condenser 56 charges, the voltagethereacross increases in a positive direction, and is applied to the,control electrode 57 of the output tube 58, which is con-.

nected in a cathode-follower type of circuit having an output loadresistance 64. As the voltage of the control electrode 57 becomesgreater in a positive direction, the cathode 62 follows the change, andtherefore a positively increasing voltage appears at the load resistance64 and at the output terminal 71 as is indicated by the numeral 86 onthe saw-toothed output signal 87. The constant-voltage device 66functions to provide linearity of the output signal at the terminal '73.as is more fully described in the copending application to whichreference is made hereinbefcre.

The positive voltage appearing at the load resistance 64 is tapped offat the tap 73 and applied through the resistance 72 to the first grid 41of the timing tube 13. When this voltage becomes sufiiciently positivein value, electrons from the cathode 16 will flow through the first grid41 and through the second grid 12 (which is no longer rendered negativeby the signal source 11) to the anode 17 thereby returning the tube 13to its first stable state. rent through its load resistance 22, and thevoltage thereat changes in a positive direction to a value nearer thatof the voltage source 19. This positive voltage at the collectorelectrode 18, is applied to the control electrode 26 of the couplingtube 27 and hence the voltage at the cathode 37 thereof changes in apositive direction, thereby rendering the discharge tube 47 conductive,whereupon the condenser 56 is quickly discharged there-.

through. The output voltage 87 then ceases to increase, and quicklyreturns to its quiescent value, as indirected by the numeral 8%. Whenused to provide deflection voltages for a cathode-ray tube, the positiveportion 35 of the output signal 87 represents the active partof theelectron beam sweep and the negative portion 85 represents the return.trace of the electron beam sweep.

By adjustment of the collector load resistance 22, the invention can beused to provide either recurrent or nonrecurrent sweep signals, in thefollowing manner. If the collector load resistance 22 is made to have asufficiently small value, the circuit will remain in its first stablestate until triggered by the source 11 of synchronizing signals. Thatis, each synchronizing signal from the source 11 will produce a singlesawtooth output signal in the manner described above. If the collectorload resistance 22 is made to have a sufficiently large value, however,the sawtooth signal output can be made recurrent and a series ofsawtooth output signals will be provided, even if no synchronizingsignals are applied to the second grid 12 of the timing tube 13. v

The recurrent sweep occurs in the following manner. When, at the end ofa sweep, the discharge tube 7 is made conductive by applying a positivevoltage tojits control electrode, the condenser 56 discharges throughthis tube. When the condenser 56 has discharged sufii- The collectorelectrode 18 .now draws less cur-,

ciently, the anode of the discharge tube 47 will become relatively lesspositive in its voltage, whereupon the positive-polarity controlelectrode '46 will begin to draw current and the anode 49 will cease todraw current. At this moment, the output signal 87 has reached itsquiescent or zero value at the bottom of the return-trace portion 88.The current to the control electrode 46 flows through the coupling tube27 from the source 19 of voltage. Due to the effect of increased currentflowing through the inherent resistance of the coupling tube 27, thevoltage of the control electrode 46 of the discharge tube 47 will changein a negative direction. This negative voltage is applied through theresistance 39 to the first grid 41 of the timing tube 13 and therebycauses this tube to change into its second stable state whereby a newsawtooth output signal is generated. This procedure continuesconsecutively, thereby producing a continuous succession of sawtoothoutput wave forms. The recurrent operation may be synchronized bysignals from the source 11. Certain other circuit elements also may beadjusted to selectively obtain recurrent or non-recurrent operation.

The coupling tube 27, in addition to its functions already described,performs the function of stabilizing the voltage at the controlelectrode 46 of the discharge tube 47, as follows. It will be noted thatthe positive output signal which is fed back through the resistance '72to the first grid 41 of the timing tube 13, is also fed through theresistance 39 to the control electrode 46 of the discharge tube 47.Under certain conditions, this could cause an undesirable effect ofmaking the tube 47 conductive prematurely whereas it is desirable, inthe operation of the circuit, that the tube 47 should not becomeconductive until after the timing tube 13 changes to its first stablestate via the feedback signal to its first grid 41.

The coupling tube 27 prevents this undesirable effect by acting as avoltage regulator for the feedback voltage at the control electrode 46.When the voltage at the control electrode 46 tends to change in apositive direction, the cathode 37 of the coupling tube 27 also tends tochange in a positive direction. This tendency results in less currentflowing through the coupling tube 27 whereby its cathode voltage tendsto become more negative. These counteractive effects tend to stabilizethe voltage at the control electrode 46 of the discharge tube 47 withrespect to the output signal feedback voltage.

in the embodiment shown in Figure 2, the feedback tube 76 providesadditional stability for the discharge tube 47, as follows: As has beenstated above, there is an undesirable tendency for the voltage of thecontrol electrode 46 of the discharge tube 47 to change in a positivedirection due to the feedback of the output signal. The feedback tube 76counteracts this tendency by applying a counteracting feedback voltageto the cathode 48 of the discharge tube 47. The output voltage fromthetap 82 is-fed to the control electrode 81 of the feedback tube 76,and is thereby cathode-coupled to the cathode 48 of the discharge tube47. This novel arrangement causes the voltage at the cathode 48 tochange substantially the same amount and in the same direction ofpolarity as the control electrode 46 thereof, as far as the feedbackvoltage of the output signal is concerned. Therefore, there is nopossibility of the discharge tube 47 becoming conductive prematurelybefore the timing tube 13 is actuated into its first stable state.

In the circuit of Figure 3, the diode rectifier 33 functions to delaythe feedback of the output signal to the first grid 41 of the timingtube 13 until the signal is of sufiicient magnitude to actuate the grid41 and return the timing tube 13 to its first stable state. Thus, thereis no danger of the feedback signal actuating the discharge tube 47before it is of sufiicient magnitude to actuate the first grid 41 of thetiming tube 13. The delay in the feedback signal may be controlled byadjustment of the tap 73 on the load resistance 64.

The various novel stabilization means, above described, cause the grid41 of the timing tube 13 to be actuated before the grid 46 of thedischarge tube 47 becomes actuated, both at the time when the negativesweep-actuating signal is applied to these grids, and also when thepositive return-sweep-actuating feedback signal is applied to thesegrids. This feature is particularly desirable for the following reasons:In a conventional circuit having a signal source connected to controlelectrodes of two tubes, a positive signal will actuate a first one ofthese tubes before it actuates the second tube, depending on the gridand cathode biases of the tubes. A negative signal, however, willactuate the second tube before it actuates the first tube. Such aconventional arrangement lacks the required stability for a sweepcircuit such as is here described. In the novel stabilization circuitsherein described, the two tubes involved, i. e., the switching tube 13and the discharge tube 47, are biased so that a negative signal willactuate the switching tube first; and the stabilizing circuits,hereinbefore described, cause the switching tube to again be the firstactuated by a positive signal, after which the discharge tube isactuated.

The recurrent sweep rate may be adjusted by means of the variableresistance 51. This sweep rate may also be varied by adjusting thevalues of the condenser 56, the voltages 19 and 34, and the tap 73 onthe output resistance 64. The source 11 of synchronizing signals may beemployed to obtain synchronization of the sweep circuit.

it is to be noted that the constant-voltage tube 28, shown in differentpositions in the figures of the drawing in order to provide properoperating voltages for the tubes, could be replaced by a resistance ifdesired. However, since the signal from the collector element 18 iscoupled through the constant voltage device 28 to the first grid 41, aresistance at this point would reduce the amount or" signal thuscoupled. Therefore, a constant-voltage device is preferable at thispoint in order to transmit the full magnitude of this coupling signal,and at the same time provides proper operating voltages.

The circuit of Figure 4 functions as follows: The timing tube 13 isnormally in its first stable state with current flowing to the anode 17through its load resistance 21 and with a relatively small amount ofcurrent flowing to the collector electrode 18 through its loadresistance 22; thus the anode 17 and output terminal 101 will have arelatively negative polarity of voltage 106 and the collector electrode18 and its output terminal 1G2 will have a relative positive polarity ofvoltage 107.

When the source 11 of synchronizing signals renders the second grid 12negative, the tube 13 changes into its second stable state, because ofthe feedback provided through the constant voltage device 23 as has beenexplained above. in this second stable state, the anode 17 draws nocurrent and thus the anode and its output terminal 161 have a relativelypositive voltage 108; the collector electrode 13 now draws currentthrough its load resistance 22 and hence this electrode and its outputterniinal 1 32 have a relatively negative polarity of voltage 189. Thetube 13 will tend to remain in its second stable state even though thenegative synchronizing signal is removed from its second grid 12, aslong as the first grid 41 is maintained at a relatively negativepotential.

The timing tube 13 is returned to its first stable state by applying apositive-polarity trigger signal to its first grid 41. The circuit showsalternative means, selectable by the switch 94, for applying apositivepolarity trigger signal to the first grid 41. When the switch 94is arranged to connect the positive-polarity trigger source 92 to thefirst grid 41, the circuit operates as follows: The positivepolaritytrigger source 92 provides trigger pulses which are applied to the firstgrid 41 in a controlled phase with respect to the negative-polaritytrigger signals applied to the second grid 12 by the source 11. If it isdesired to obtain square wave signals at the output terminals 101 and162, the phase of the positive-polarity signals of the source 92 shouldbe such that these positive-polarity sig- '7 nals will 'occur halfwaybetween the negative-polarity pulses produced by the source 11. .Otheroutput wave shapes at iheiterminals 191 and .102 may be produced byvaryingithisphase relationship.

When the switch 94 is arranged to connect the phase .delay device 133 tothe list grid 41, the circuit operates as follows: When the tube 31 ischanging to itsse'cond stable state and the voltage at the outputterminal 191 is changing in .a positive direction as indicated by thenumeral 111, this positive signal is delayed by the delay device 103 andis then coupled to the first grid 41. .Wben the first grid 41 is thusrenderedpositive in polarity, the tube 13 returns vto its first stablestate. The phase delaydevice 163 may comprise a series-connectedresistance 112 land .a shunt-connected capacitance 113, as shown-inFigure 4. a

The circuit of Figure 4 will generate a square or rectangular outputwave each time a negative trigger pulse is applied to its second grid12. Byapplying continuously repetitive negative-polarity trigger signalsto the second grid 12, 2. continously repetitive push-pullrectangularwave output signal may be obtained at the output terminals101 and 102. The exact shape of the output signal maybe varied byadjusting the phase delay of the positive trigger source W, or of thephase delay device 163 such as by varying the value of the resistance112 or of the capacitance 113.

The embodiment shown in Figure 5, comprising the load tube 95 andassociated components, functions to partially overcome the undesirableeffects of the stray capacitance 110, which is inherent in the circuit.When a positive or negative signal is applied to the control electrode45 of the discharge tube 47 from the collector electrode 18 through thecoupling tube 27, the stray capacitance 119 tends to absorb thehigh-frequency components of the leading edge of the signal, so that thesignal is delayed in building up to its operating level at the controlelectrode 46.

The load tube 95 provides a cathode load for the coupling tube 27. Theload tube 95 also speeds up the operation of the discharge tube 47, asfollows: When ever a positive or negative signal is generated at thecollector electrode 18 of the timing tube 1.3.21 corre-;

spending signal of opposite polarity is generated at the anode 17, ashas been explained-with refe ence to Figure 4 of the drawing. Thissignal from the anode 17 is "coupled through the condenser 10$ to thecontrol electrode 189 of the load tube 95, where it is amplified andphase-inverted and'fed from the anode 96 to the control electrode 46 ofthe discharge tube 47 in phase with the signal which is-coupled to thecontrol electrode 46 from the collector electrode 18 of the timing tube13. The amplified iii-phase signal at the anode of the load tube 95,speeds the buildup time of signals at the control electrode 46, thuscounteracting the adverse effect of the stray capacitance ill}. Theamplification or" the tube 95 is controlled by the variable resistance9?. In the circuit of Figure 5, the constant-voltage device 28 shown inFigures 1, 2 and 3, is not employed since the value of the resistance 84is relatively small compared to the cornparatively high resistance ofthe load tube 95, and hence only a small amount of signal is dissipatedin the resistance 84 whichacts as a voltage ider in combination with theplate resistance of the load tube 95.

An important feature of the invention is that the repea ing tubel3=occurs in accordancewith the voltage levelof the output signal, anditlius switching rat ultimately depends upon the single timeeconstanticircuit which controls the rate'of-rise of the output sawtooth -:sweepsignal.

While preferredembodirnents of .the invention have been described,modifications thereof will be apparent to those skilled in the :art, andyet will fall within the scope of the invention.

The true scope of the invention is defined in the-following claims.

What is claimedis:

l. A sawtooth-wave.generator comprising .a tube 0 the gated-beam typehaving a cathode, a first grid, a collector electrode, a second grid andan :anode; a first source of voltage connected to said anode, .a secondsource of voltage, a first impedance connected :between second voltagesource and said-collector electrode, source of synchronizing signalsconnected to said second grid, a saw-tooth wave forming-condenser,.athird'rsource of voltage, a second impedance connected between saidthird voltage source and said sawtooth wave forming condenser, adischarge device connected in parallel with said sawtooth wave formingcondenser and containing a control electrode, means electricallyconnecting said collector electrode to saidlirst grid and to saidcontrol electrode, utilization means connected to said sawtooth waveforming condenser to utilize a sawtooth wave produced therein, and meansconnected to apply said sawtooth wave to said first grid.

2. The device in accordance with claim 1, in which said utilizationmeans comprises a cathode-follower circnit. having an input electrodeconnected to saidsawtooth wave forming condenser and a cathode loadimpedance connected to said first grid.

3. The device in accordance with claim 1, in which a constant-voltagedevice is connected in series between said collector electrode and saidfirst grid.

4. The device in accordance with claim '1, in which said meanselectrically connecting said collector electrode to said first grid andto said control electrode comprises a cathode-follower circuit having aninput electrode connected to said collector electrode and a cathodeconnected to said first grid and control electrode.

5. The device in accordance with claim 4, in which a load impedance isconnected to said cathode of said cathode-follower, comprising anelectronic tube having I an anode connected to the junction of saidcathode of said cathode-follower and said control electrode and saidfirst grid, and containingla control; grid, a capacitance between saidjunction and ground, an a capacitor connected between said control-gridand said anode of said tube of the gated-beam type.

6. The device in accordance with claim 1, in which a resistor isconnected between said first grid and said control electrode.

7. The device in accordance with claim 1, in which said first impedanceis variable to provide selectivelyrecurrent or non-recurrent sweeps.

8. The device in accordance with claim 1, in which said discharge devicecontains a cathode; anelectrical impedance connected in series with saidcathode of-said discharge device; and a feedback tube having an anodeconnected to a source of voltage, a control grid connected to saidsawtooth wave utilization circuit, and :a cathode connected to saidcathode of said discharge device.

9. The devicein accordance withclaim l, in which said connection betweensaid collector electrode and said first grid and control electrodecomprises an electronic tube having an anode connected to a source ofvoltage, a control grid1connected to said collector electrode, and acathode connected to said control electrode; and aresistor connectedbetween said control electrode and said first grid. I

10. The device in accordance with claim .1, in which a diode member isconnected in series between said utilization circuit and said firstgrid.

11. The device in accordance with claim 1, in which the value of saidfirst impedance is sufiiciently small so that the device generates asingle electric signal when actuated by a single one of saidSYIlCilIOIiiZlETrg signals.

12. The device in accordance with claim 1, in which the value of saidfirst impedance is sufiicientry large so that the device generatesrecurrent electric signals.

13. A rectangular-wave generating circuit comprising a tube of thegated-beam type having a cathode, a first grid, a collector electrode, asecond grid and an anode; a first impedance, a source or" voltageconnected through said impedance to said anode, a second impedance, asource of voltage connected through said second impedance to saidcollector electrode, an electrical signal transferring connectionbetween said collector electrode and said first grid, a source ofnegative trigger signals connected to said second grid, and a source ofpositive trigger signals connected to said first grid.

14. The device in accordance with claim 13, including means to derivesaid positive trigger signals in accordance with said negative triggersignals.

15. An electrical circuit comprising a tube of the gatedbeam type havinga cathode, a first grid, a collector electrode, a second grid, and ananode, a first source of voltage connected tosaid anode, a second sourceof voltage, an impedance connected between said second voltage sourceand said collector electrode, a source of synchronizing signalsconnected to said second grid, a signal input terminal, means connectedthereto for generating a positive going sawtooth wave voltage, saidmeans having an output terminal, means electrically connecting saidcollector electrode to said first grid and to said input terminal, andmeans electrically connecting said output terminal to said first grid.

16. A rectangular-wave generating circuit comprising a tube of thegated-beam type having a cathode, a first grid, a collector electrode, asecond grid and an anode; a first impedance, a source of voltageconnected through said impedance to said anode, a second impedance, asource of voltage connected through said second impedance to saidcollector electrode, an electrical signal transferring connectionbetween said collector electrode and said first grid, a source ofnegative trigger signals connected to said second grid, a source ofpositive trigger signals connected to said first grid, and'a constantvoltage device connected between said collector electrode and said firstgrid.

17. A rectangular-wave generating circuit comprising a tube of thegated-beam type having a cathode, a first grid, a collector electrode, asecond grid and an anode; a first impedance, a source of voltageconnected through said impedance to said anode, a second impedance, asource of voltage connected through said second impedance to saidcollector electrode, an electrical signal transterring connectionbetween said collector electrode and said first grid, a source ofnegative trigger signals connected to said second grid, and a source ofpositive trigger signals connected to said first grid, said source ofpositive trigger signals comprising a phase-delay device connectedbetween said anode and said first grid.

References Cited in the file of this patent UNITED STATES PATENTS2,060,095 Mathes Nov. 10, 1936 2,143,397 White Jan. 10, 1939 2,228,084Murcek Jan. 7, 1941 2,275,016 Koch Mar. 3, 1942 2,404,919 Overbeck July30, 1946 2,456,029 Snyder, Jr Dec. 14, 1948 2,469,031 Canfora May 3,1949 FOREIGN PATENTS 620,585 Great Britain Mar. 28, 1949

